Robert De Niro is far from raging when discussing his latest role. In fact, he's kind of a softie.

Appearing on Monday's edition of Katieto promote his Oscar-nominated flick The Silver Linings Playbook, the Raging Bull star listened quietly as his director, David O. Russell, talked about how his own son has a mood disorder similar to the one the movie's main character, played by Bradley Cooper, suffers from.

But when he was asked by Katie Couric if he felt a greater responsibility being part of a project his director was "personally invested in," De Niro uncharacteristically choked up and began crying.

"Oh, of course," the 69-year-old film legend said, quickly getting teary-eyed. "I don't like to get emotional, but I know exactly what [David] goes through."

"Understood. Some of the same experiences he's had with his son," the journalist-turned-talk show host replied. "So clearly this became an important cathartic experience for all of you, you know, a communal experience."

In discussing the mental illness, Russell subsequently recalled meeting with De Niro in his apartment about the script and how the thesp was deeply affected by the subject.

"I thought he was having hay fever, and I realized he was having an emotional reaction," said the filmmaker. "I sat there and watched Robert De Niro cry for 10 minutes and I said, 'Wow, he's really connecting with this material and this would be a beautiful thing if it could work out, because I think his heart would be there,' and it is there."

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